e20668 Background: Cachexia is among the most debilitating and life-threatening aspects of cancer. It represents a metabolic syndrome affecting essential functional circuits involved in the regulation of homeostasis, and includes anorexia, fat and muscle tissue wasting. The anorexigenic peptide alpha-MSH is believed to be crucially involved in the normal and pathologic regulation of food intake. It was speculated that blockade of its central physiological target, the melanocortin (MC)-4 receptor, might provide a promising anti-cachexia treatment strategy. This idea is supported by the fact that in animal studies, agouti-related protein (AgRP), the endogenous inverse agonist at the MC-4 receptor, was found to affect two hallmark features of cachexia, i.e. to increase food intake and to reduce energy expenditure. Methods: Two recently discovered, non peptidic, chemically unrelated, orally active MC-4 receptor antagonists penetrating the blood brain barrier were studied. Specifically, the influence on food intake in healthy mice, and effects in the murine C26 cancer-cachexia model were investigated. Results: Both compounds were found to distinctly increase food intake in healthy mice. Moreover, in mice subcutaneously implanted with C26 adenocarcinoma cells, repeated oral administration (starting the day after tumor implantation) of each of the two compounds almost completely prevented tumor induced weight loss, and diminished loss of lean body mass and fat mass. Conclusions: In contrast to the previously reported peptidic and small molecule MC-4 antagonists, the compounds described here work by the oral administration route. In the light of patient care, orally active compounds might offer a considerable advantage for the treatment of cancer cachexia. [Table: see text]

Inhibition of the cysteine protease calpain is a promising strategy for the treatment of muscular dystrophies including Duchenne Muscular Dystrophy. For the treatment to be effective, uptake of the inhibitors into the muscle cells is a prerequisite. A series of alpha-ketoamide calpain inhibitors carrying various muscle cell targeting capping groups was synthesized. Compounds with charged or highly polar targeting groups were not able to cross the cellular membrane. Introduction of lipoic acid as end cap yielded cell permeable calpain inhibitors with nanomolar potency.

Dipeptide-derived alpha-keto-amide compounds with potent calpain inhibitory activity have been identified. These reversible covalent inhibitors have IC(50) values down to 25nM and exhibit greatly improved activity in muscle cells compared to the reference compound MDL28170. Several novel calpain inhibitors have shown positive effects on histological parameters in an animal model of Duchenne muscular dystrophy demonstrating their potential as a treatment option for this fatal disease.

Chronic inflammation is a secondary reaction of Duchenne muscular dystrophy and may contribute to disease progression. To examine whether immunosuppressant therapies could benefit dystrophic patients, we analyzed the effects of cyclosporine A (CsA) on a dystrophic mouse model. Mdx mice were treated with 10 mg/kg of CsA for 4 to 8 weeks throughout a period of exercise on treadmill, a protocol that worsens the dystrophic condition. The CsA treatment fully prevented the 60% drop of forelimb strength induced by exercise. A significant amelioration (P < 0.05) was observed in histological profile of CsA-treated gastrocnemius muscle with reductions of nonmuscle area (20%), centronucleated fibers (12%), and degenerating area (50%) compared to untreated exercised mdx mice. Consequently, the percentage of normal fibers increased from 26 to 35% in CsA-treated mice. Decreases in creatine kinase and markers of fibrosis were also observed. By electrophysiological recordings ex vivo, we found that CsA counteracted the decrease in chloride conductance (gCl), a functional index of degeneration in diaphragm and extensor digitorum longus muscle fibers. However, electrophysiology and fura-2 calcium imaging did not show any amelioration of calcium homeostasis in extensor digitorum longus muscle fibers. No significant effect was observed on utrophin levels in diaphragm muscle. Our data show that the CsA treatment significantly normalized many functional, histological, and biochemical endpoints by acting on events that are independent or downstream of calcium homeostasis. The beneficial effect of CsA may involve different targets, reinforcing the usefulness of immunosuppressant drugs in muscular dystrophy.

Peptide-derived keto-carbonyl compounds with potent calpain inhibitory activity have been identified. These reversible covalent inhibitors exhibited greatly improved activity in muscle cells compared to the reference compound MDL28170 with IC50 values in the nanomolar range. Several compounds have shown positive effects on histological parameters in an animal model of Duchenne muscular dystrophy demonstrating their potential as a treatment option for this fatal disease.

Duchenne muscular dystrophy is a severe X-linked hereditary disease caused by the absence of functional dystrophin. The dystrophin-deficient mdx-mouse strain is a widely used animal model for dystrophin-deficiency. Several therapeutic approaches for muscular dystrophy have been proposed by different laboratories. In order to compare the efficacy of these therapies in the mdx-mouse, it is essential to implement standardized protocols for the assessment of functional and histological parameters in this mouse model. Here, we determine that the minimal 'Feret's diameter' is a geometrical parameter that allows for reliable measure of muscle fiber cross-sectional size. Using this geometrical parameter we calculate variance coefficients of the muscle fiber size and provide reference values for the quantitative assessment of dystrophic symptoms in frequently investigated muscles of wild-type and mdx-mouse. In addition, we compare the variance coefficients of the muscle fiber size with the percentage of muscle fibers with centralized nuclei; another histological hallmark of muscular dystrophy.